Flesh out some of the extended symbol table work
Wrote docs for better keywords; still needs implementation
Major overhaul: uses new extended symtab

This commit not only uses the new extended symbol table functinality,
but also adds new keywords to get different kinds of compiler
behavior.
Added to ignore file
Hypothesis: is cop_hints_fetch_pvs the best way to get at the hints hash?
Conclusion: cop_hints_fetch_pvs is not the right tool
Hypothesis: Did I screw up my last attempt at hint hash use?
Lexical symbol sharing is not yet working
Correctly serialize the state pointer; minor convention cleanups
Add basic error reporting tests
Partial fixup of error message does not say <string> anymore
Finished basic error reporting fixups
Removed diagnostic printout in test script
Found a general bug in parser line counting, which shows up in error reporting
Hypothesis: can I avoid trouble by setting the appropriate compiler flags?
Conclusion: compiler warnings can save me from segfaults
Fleshed out some ideas for the compiler options setting
Added some notes and preliminary work for loading libperl
Cleaned up external symbol table protocol
Switched clib -> cshare