Update xctool to v0.2 for Xcode 6 support

Closes #32417.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
xctool: update 0.2 bottle.
Pass command and arg list into ErrorDuringExecution constructor
Make install name debug output more readable
Remove obsolete nil guard

This was added in 3a7a3619f7016c75c3e53e944221bf7f6354a63b to make the
tests pass, but this method is now stubbed out in the tests, so we can
assume $? will be non-nil.
Split out Boost.Python
Use boost-python instead of boost => with-python

Boost.Python support in Homebrew is moving from the boost formula to a
new boost-python formula. This commit updates formulas that were using
boost --with-python to use boost-python instead.
boost: update 1.55.0_3 bottle.
boost-python: add 1.55.0 bottle.
ledger: update 3.0.3_1 bottle.
libpst: update 0.6.55_1 bottle.
libtorrent-rasterbar: update 1.0.2_1 bottle.
mapnik: update 2.2.0_3 bottle.
pyexiv2: add 0.3.2_1 bottle.