Compiler: attach debug to variable declaration

Compiler: attach debug to variable declaration

Conflicts:
	compiler/code.ml

more
Compiler: improved propagation of debugging information
Merge branch 'master' into vardecl_dbg

Conflicts:
	compiler/generate.ml
	compiler/parse_bytecode.ml
Compiler: Parse_bytecode.State.start_block does not need the pc anymore
Merge pull request #89 from ocsigen/vardecl_dbg

Compiler: improved propagation of debugging information