ENH: PyTables Enhancements for future
## open (not in any particular order)
1. add support for other dtypes in table columns (datetime,date,unicode)
2. Implement variable length strings in a parallel VLArray (and synchronize): https://github.com/PyTables/PyTables/issues/198
3. revisit Term syntax - can we do better / more readability?
   3a. implement `or` in Terms (maybe use pyparsing like syntax)
4. implement WORMTable
5. one big area is to test whether data columns really are slower; it thus may make sense to make data columns = True the default (but not necessarily index them). see https://groups.google.com/forum/m/?fromgroups#!topic/pydata/cmw1F3OFJSc - see the end of this post for some perf tests, so this is prob not a good idea after all
6. add `export` function, to export to different PyTables formats(an easy to read table for R (partially done), and output a GenericTable)
7. provide better access to columns that are data_columns (as we can directly select them) - see `read_column`, expand this to the entire table (if possible), allows one to avoid selecting all columns in a table (and then reindexing), this works if `columns` argument is provided to select or inferred from the where.
8. add out-of-core computation support (see my comment about 1/2 down in #622), this is partially supported now that we have an iterator (#3078)
9. add a method to create a table structure (`create_table`)?, w/o actually appending, so don't have to add parms in each call to append.
10. Support a better mechanism for table splitting `Splitter`? that a user can specify how to split (rather than a dict); then store this object, so can automatically recreate the resulting table (enable for both Storer and Table objects)
11. Optimize table appending, I think we can do better! (GH #3537) makes some improvements
12. allow `itemsize='truncate'` to allow subsquent appends to proceed with string truncation (on specific columns)
13. allow where in `select_column`, return a properly indexed Series, add option to include the index (`use_index=True?`)
14. Better deal with a very long list as input to a `Term`, but running multiple `or` sub-queries
15. Add support for coulumn oriented tables, dep is `carray`, http://carray.pytables.org/docs/manual/
## done
1. DONE (GH #2401): access store paths via path notation / dot notation (GH #2755)
2. DONE (GH #2497): add to docs (GH #2397) - issues about reading/writing concurrently in threads/processes
   http://sourceforge.net/mailarchive/message.php?msg_id=30190886
3. DONE (GH #2497): support panelnd (GH #2242)
4. DONE (GH #2561): Should DataFrames be automagically indexed on 'index' (prob yes), but then should have a flag in append/put, and enable passing of the indexing options
5. DONE (GH #2497): Check if create_table_index changes the current index if different options are passed
6. DONE (GH #2561): for writing add chunk keyword to select to provide generator like behavior - each call to return the next chunk of data
7. DONE (GH #2561): support multi indexes on tables
   5a. DONE real dtype integration is coming on PR #2708 (eg even though 0.10.1 will actually read/write float32 columns u can't really do much with them w/o having them upcasted) - in any event I think HDFStore will accommodate this already. but more testing needed
8. DONE iterator support in `select`, http://stackoverflow.com/questions/14614512/merging-two-tables-with-millions-of-rows-in-python (GH #3078)
9. DONE (GH #3531) support timezones in datelike columns (index should be ok already) (scott?), (GH #2852)
