CWallet::TopUpKeyPool() takes optional pool size argument

Also, GetKeyPoolSize() now returns an accurate type, unsigned int.
RPC: keypoolrefill gains optional size parameter
Detect any sufficiently long fork and add a warning.

Such a fork is defined as being at least 7 blocks long and
having a tip which is within 72 blocks of our best block.
Call the -alertnotify script when we see a long or invalid fork.
Better warning/"alert" messages for large-work forks.
Compile into build_test when creating bitcoin-qt_test
do not call BuildMerkleTree() unnecessarily twice
Merge pull request #2890 from cozz/cozz1

do not call BuildMerkleTree() unnecessarily twice
Add missing 0x prefix in chainparams.cpp
Merge pull request #2892 from r000n/master

Add missing 0x prefix in chainparams.cpp
Merge pull request #2658 from TheBlueMatt/forkalert

Detect any sufficiently long fork and alert the user just like any other alert
Removed duplicate files.

Left behind after the change to Markdown.
Merge pull request #2899 from super3/master

Removed duplicate /doc files.
Merge pull request #2877 from gavinandresen/qt_unittest_makefile

Compile into build_test when creating bitcoin-qt_test
Merge pull request #2776 from jgarzik/keypoolsize

RPC: keypoolrefill now permits optional size parameter, to bump keypool