Add support for armv8 in the PLCrashReportTextFormatter

Issue: PLCR-495
Fix typo in the fuzz testing harness.
Fix handling of ARM64/ARMv8 cputype/subtype.

Issue: PLCR-495
Add @internal documentation tag on plcrash_async_symbol_strategy_t
Fix parsing of NS_ENUM and NS_OPTIONS enum macros.
Fix TODO item in the Mach API documentation
Merge branch 'master' into landonf-PLCR-495-armv8
Set an arm64-specific version.
Add missing break in switch statement

Issue: PLCR-495
Update project for compatibility with the Xcode 5 release.

ARM64 now requires a minimum target OS version of 7.0.
Work around rdar://15042905 by mapping a segment other than __LINKEDIT.

On ARM64, The call to getsegmentdata() returns an invalid size value
that extends beyond the pages mapped for the segment; our tests crash
when memcmp() reads past the end of the mapped pages in the buffer
returned by getsegmentdata().

This seems to be caused by vmsize not being adjusted after the libPLCR
MH_OBJECT is linked with symbols stripped. If we disable symbol
stripping, the issue also disappears.

Whether this will impact anything beyond naive use of getsegmentdata()
is an open question, but since we can't ship with the private symbols
visible due to namespacing issues

The bug has been filed with Apple as rdar://15042905.

Issues: PLCR-495, PLCR-498
Fix incorrect dereferencing of the current SP, rather than the FP.
Switch to a 64-bit bitfield for tracking available registers, as to accomodate arm64's 34 registers.

Issue: PLCR-495
Remove unused #include.
Always return an error on failure, rather than returning the previously initialized err value (which may be PLCRASH_ESUCCESS).
Skip NULL method lists rather than returning an error.

The base method list will be NULL if no methods are defined for the
class/metaclass.

Issue: PLCR-495
Break out parsing of method lists into a seperate function.

This is intended to allow us to also parse category method lists.

Issue: PLCR-495
Implement a work-around for ARM64's tagged metaclass isas.

Issue: PLCR-495
Implement iteration of the category list (but not parsing of the categories).

Issue: PLCR-495
Convert PLCrashAsyncObjCSection.c to C++; we'll use templates to handle the 32-bit/64-bit split.

This also fixes an issue caught when building C++; the
deprecated plcrash_async_read_addr() returns a kern_return_t,
but the result was interpreted as a plcrash_err_t (this is why
plcrash_async_read_addr() is now deprecated).

Issue: PLCR-495