Updated sequence import and parsing for single character alphabets
Instead of using a string for each character, I created functions
within StochHMM::track to deal with characters.  In StochHMM::sequence
if the tracks are single letter tracks then use the char function
in Track.

Also fixed function within pwm.cpp for Variable spacer motifs and
Simple motifs.
Changed definition of SCALING VALUES to SCALING FUNCTIONS
Fix premature exit when doing posterior with multiple fasta file

When calling posterior, removed a return from main that caused a
premature exit.
Add sparseArray and dynamic_bitset for re-write of ExternDefs
Merge branch 'development'

Conflicts:
	src/StochHMM.cpp
Update version number to v0.24
Fix I/O lag in print_posterior function

Changed calls to std:: cout to create a string then print string
at the end of the function
Updated makefile to Optimization level 3