Convert from the C-based LLVM Disassembler shim to the full MC Disassembler API's.  
Calculate "can branch" using the MC API's rather than our hand-rolled regex'es.
As extra credit, allow setting the disassembly flavor for x86 based architectures to intel or att.

<rdar://problem/11319574>
<rdar://problem/9329275>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@176392 91177308-0d34-0410-b5e6-96231b3b80d8