Version v3.0.0

• Implement compatibility with Vector's ASAP2 Creator and allow creation of a2l elements using the same special comment syntax
• Implement additional modes for file merges.
  The standard so far was to keep both conflicting elements. Now the --merge-preference option can be used to always use the existing version or the new version instead.
• Add a manual for a2ltool.
• Support non-standard SYMBOL-LINK notation, where the compile unit name is used as a prefix of the real symbol name
• Implement the ability to update VAR_ADDRESS info of VAR_CHARACTERISTIC
• Handle negative bit-offsets in DWARF2 debug info correctly instead of panicing
• Increase the size of the containing type for bitfields that extend past the end of their nominal containig type.
• Add more plausibility checks to --check