Created branch for ticket #714
Fixed issue #715 "Avoid strings to last over the a line in input history"
Fixed issue #716 "Shorten string variables in GUI"
Implemented ticket #713 "Control flow headers should accept interrupts"
Implemented ticket #712 "Eigenvalues and eigenvectors from NANs"
Fixed issue #711 "'shuffle()' also suffers from a race condition"
Fixed the changes log for #669
Added the new commands is_file and is_dir to the changes log. Related to #669.
fixed an issue where a dot in a directory name would be misinterpreted as a file extension. Relates to ticket #669.
fixed the open issues with the is_dir and is_file functions for the ticket #669.