implemented simple gdb logging command

set logging redirect ist disabled as we have to parse the
output every time to keep the state in sync
set gdb height to 0 to disable interactive paging

we want to parse the whole output anyway so there is
no good point in doing paging
implemented disas syntax flavor (intel, att)

this introduces a SyntaxStyle enum, but the
set_disassembly_flavor function can be called
with either string or SyntaxStyle enum.
such fail, ninja file ninjas himself into the tree