Add user option to enforce features during feature selection within MOSES
Fix compile boost::program_option error
Replace deme_expander::_demes type boost::ptr_vector<deme_t> by std::vector<deme_t>

The reason boost::ptr_vector was used is because deme_expander would
be initialized with NULL deme before multiple deme were supported, but
an empty vector provides that anyway.
Implement enforce features during feature selection within MOSES
Fix bunch of compile errors
Structural changes to have demes be vector of vectors of demes (for subsampling)
Rename behave_cscore::ignore_idxs by behave_cscore::ignore_cols
Add subsampling parameter + allow spawning subsample-deme
Keep track of the number of evaluations directly in deme_t

Instead of having the optimizer return the total number of evaluations
and the number of evaluations to reach the best candidate, this
information is kept in the class instance_set (or later typedef as
deme_t).

This simplifies a bit the API.
Add behave_cscore::ignore_rows
Move subsample_deme_filter_parameters from deme param to metapop param and add more subsampling parameters
Fix subsampling to reset the removed rows after subsampling
Rename istreamTable to istreamTable_OLD and istreamTable_NEW to istreamTable
Add TTable in Table and related IO functions

TTable is a structure to hold timestamps. Associating to each row a
timestamp.
Add boost date time linking
Add label support in TTable
Add TTable support in table IO
Move TTable upper and implement TimedCounter

TimedCounter is a Counter when the items have timestamps. TimedCounter
offers facilities to retreive counts and other stats ignoring the
timestamps.
Replace Counter by TimedCounter in CTable
Fix ostreamCTable (proper handling of empty timestamp)