This makes it useable for non-global locks such as the wallet and
keystore locks.

There were quite a few places where assert() was used with side effects,
 making operation with NDEBUG non-functional.  This commit fixes all the
 cases I know about, but also adds an  #error on NDEBUG because the code
 is untested without assertions and may still have vulnerabilities if
 used without assert.

Also changes mempool to store CTxMemPoolEntries
to keep track of when they enter/exit the pool.

GetValueIn makes more sense as a CTransaction member.

This dead code can be resurrected from git history if
transaction replacement is ever implemented. Keeping
dead code in the source is a bad idea, because it implies
it was tested and worked at some point, which is not true.

  relicts from the CTransaction refactor.

- example: if util.h includes stdint.h, remove it from util.cpp, as
  util.h is the first header included in util.cpp

Use misc methods of avoiding unnecesary header includes.
Replace int typedefs with int##_t from stdint.h.
Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h.
Normalize QT_VERSION ifs where possible.
Resolve some indirect dependencies as direct ones.
Remove extern declarations from .cpp files.

No more specific handling of GUI in bitcoin core.
Replace the last usage of fHaveGUI with a fForceServer
parameter on AppInit2.

This means they are declared static, and their extern definition in
main.h is removed. Also moved CBlockIndexWorkComparator to the .cpp
file.

As block index entries have a flag for marking invalid blocks, the
'best invalid work' information can be derived from there. In addition,
remove the global from main.h

- re-work -debug help message text
- make -debug log every debugging information again (even all categories)
- remove unneeded fDebug checks in front of LogPrint()/qDebug(), as that
  check is done in LogPrintf() when category is != NULL (true for all
  LogPrint() calls
- remove fDebug ONLY in code which is NOT performance-critical
- harmonize addrman category name
- deprecate -debugnet usage, should be used via -debug=net and remove the
  corresponding global

Instead of explicitly testing for the presence of any output, and
dealing with this case specially, just interpret it as an empty
CCoins.

The case previously caught using the HaveCoins check, is now handled
by the generic outs != outsBlock test.

This required some code movement (what was CWalletTx::AcceptToMemoryPool
doing in main?), and adding a few explicit includes that used to be
implicit through init.h.

Instead of relying on cs_main (defined in a different module) to
prevent concurrent access to it.

INIT_PROTO_VERSION is the initial version, after a succesful version/verack it is increased to a negotiated version.
MIN_PEER_PROTO_VERSION could be a different value to disconnect from peers older than a specified version.

Changes the response to the 'mempool' command so that if
the memory pool has more than MAX_INV_SZ transactions (50,000)
it will respond with multiple 'inv' messages.

SendMessages() tries to acquire a cs_main lock now, but this isn't nessecary
for much of its functionality. Move those parts out of the locked section,
so they can always be performed, and we hold cs_main for a shorter time.

This removes a few unused CBlockLocator methods, and moves the
construction and fork-finding logic to CChain (which can do these
more efficiently, as it has a height-indexable chain available).
It also makes CBlockLocator independent from the validation code.

- I introduced the problem and fixed it with better readable code

Changes the maximum size of a free transaction that will be created
from 10,000 bytes to 1,000 bytes.

The idea behind this change is to make the free transaction area
available to a greater number of people; with the default 27K-per-block,
just three very-large very-high-priority transactions could fill the space.