Do not ignore UNDEF symbols

Fixes #1542
Fix #1641 -  Check $CC ASAN support
Fix S= asterisk mark
Fix 'ai' without debugger
Initial commit enhacing disasm with aop.ref and aop.refptr (x86.udis only atm)
Fix some warnings
Use -pie -fPIC for Android builds (required for Android L)
Add support for refptr analysis in ARM (gnu + capstone)
Colorize S=, Add anal.gp and better op.refs for mips and x86

- Add anal.gp to make mips.cs code analysis happy
- S= honors scr.color
- Fixed x86(capstone,udis) memrefs for mov/cmp
Honor asm.filter in VV graph and 'pi' command. Maybe we need another command to avoid breaking tests?
Rollback a reggression in 'pi'
fix invalid read errors
fix invalid writes errors
correct fix of 'invalid write' errors
Initial add 'C' to toggle colors in ascii graph (buggy+experimental)
Fix another crash in PDB
Fix use-after-free in RCoreFile/RIO
Fix out-of-bounds buffer access in PDB
Fix all latest Coverity issues
Fix another crash in PDB