Adds the foundation of pseudo types.
Adds comparison of pseudo types.

Also adds comparison of dates (our only pseudo type currently.)
Adds the time source files.
Adds construction of reql_types.

Can actually compare dates now.
Makes type_of work correctly on pseudo types.
PSEUDO -> PSEUDO_TYPE.
Adds add_txn_t to datum_t.

This helps enforce that pseudo types remain valid.
Adds an addition operation for times and durations.
Fix a bug with an infinite loop in pseudo types.
Adds subtraction for dates.
Adds in boost iso8601 parsing.
Adds a file I forgot.
Fix quickstart2.rb script.

OTS by @coffeemug.
Adds in iso8601 term to protobufs.
merged in next
crude iso8601 parsing
to_iso8601
moved more logic into pseudo_time.cc
added epoch_time
added NOW