Rename erfilter to er_filter
Separate ER Grouping algorithm into its own files
Separate shared ER functions into their own file and namespace
Separate ER word formation function into its own files
Add im_ptr member to ERStat to remove dependence on channel as an input to erFormWord
Add non-member comparison operator overloads for ERStats
Remove the ERChar struct and all depencies on it. Replace with ERStat (more simple)
Simplify pruning code and add comments with an example
Merge branch 'refactor' into rec_text
Fix LMS estimation bug. Use LMS direction to plot through top-left
corner
Implement top 2 line fitting algorithm
Use bottom line LeastMedSquares to infer line direction
Merge branch 'issue27' into rec_text