- Add namespace unwindstack everywhere so that it's easier for other
code to use the library.
- Move some of the header files into include/unwindstack so that they
can be exposed.
- Modify the headers so that only a limited number need to be exposed.
- Update the tools to use the new headers.
- Add a GetLoadBias() call on the Elf object. This prevents the need
to get the interface object out of the Elf object.
- Move the GetRelPc() call out of the Reg class, to the Elf class. It's
not always the case that a Reg object will be around when you want to
get a relative pc. The tests for this moved to ElfTest.cpp.
Bug: 23762183
Test: Unit tests pass.
Change-Id: Iac609dac1dd90ed83d1a1e24ff2579c96c023bc3