Added new DeckFloatItem with tests
Added DOUBLE enum to ParserValueTypeEnum
Renamed FLOAT to DOUBLE in JSON files, tests and some code using the enum
Added ParserFloatItem + some tests. More tests may be needed.
Removed special float/double handling in ParserFloatItem
Merge pull request #126 from AtleH/floatitem

Added DeckFloatItem, ParserFloatItem
fix the "DATES" keyword

The time of the day field was missing. The defaults for it are those
of E100.
fix the definition of the START keyword

this one had the same problems as DATES
trivial: fix end-of-file comment in Completion.hpp

that clearly was a copy-and-pasteo...
TimeMap: replace boost::gregorian::date by boost::posix_time::ptime

this is necessary because boost::gregorian::date does not have a
notion of "time during a day" which is required to specify time step
lengths less than a day...
TimeMap: simplify the initialization of the eclipse month name map slightly
TimeMap: Expose more data

basically, we now can access the beginning of a timestep its length
and the total time passed since the beginning of life, the universe
and all the rest.
TimeMap: add constructor which takes a deck

this simplifies things considerably and hopefully avoids code
excessive code duplication..
TimeMap: extend test to check "from deck construction" and the new accessor methods