getting rid of separate overlap table.
alreadyRan() now uses pytables in-kernel search
developed scheme for two-table approach with a "foreign key" to give one-to-many relationship
prepping for new style tables, paired metadata and data with foreign key pointing from data to metadata.
VersionInfo subtable added to metadata
sketch of a PairedDataStorage table
remove some Overlap X stuff.
fix VersionInfo.
get alreadyRan, extractMetaData,  and extractCols working in new pair-table scheme.
test
fixed extractMetaData:: colnames is taken from table, not row...
fractal_data.init now called from outside.
IsDescription classes are cautious about their attributes!
_get_new_meta_index() / tested
rework cudaCollect with paired table scheme, needs testing
build_table()
now allow init() to be exported.
added pycuda and pytables version info.
reverted to pytables 2.4 createTable and createGroup ... groan
_Verbose ...
add meta.row['index'] = index
store metaIndexFK properly in data row.
raise if we dont find any data for metaIndexFK
need fractal_data.init()
chc should be an int
warn if extractCols finds more than one row in
metadata with the same index. should be 1-to-many
minor fix and add TODO
Merge branch 'pytables_testing'

Conflicts:
	fractal/comparison.py
	fractal/fractal_data.py
	fractal/plot_data.py

fixed conflicts.
fixed bugs in metatable.where() searches (iterators are tricky!!!)
added some table test code.
nexec is now index