Asymptote v0.4

There have been 45 commits since v0.3.
Besides code cleanups these commits include the following changes (in no
particular order):
* king safety considers safe checks
* king safety is skipped in the end game
* initial rook evaluation
* several problems with the pawn promotions
* improvements to uci output
* reworked history history
* evaluation considers pawn mobility
* using transposition table in quiescence search
* speed optimizations