fix for issue #1834, handle NULL pointer return value from r_bin_java_read_next_attr_from_buffer()
Make rop dissassemble back from the end gadgets

- Remove some exta dissassembly steps too
- Fix up some rop search stuff
- constify is_end_gadget
- Comment the rop stuff
- Remove constant 60
- Rename rop config stuff
Add var renaming in webui and fix various bugs

- Fix missing spaces when show_functions and not in function
Fix some more disasm glitches
Fix #1839 - Fix crash in dalvik flagname parser
Fix #1842 - Crash in ROP search