New update_fsl_package script

Dedicated script for updating FSL conda packages. Does not support installation of new packages at this point in time.

Also added the fslipython wrapper for $FSLDIR/bin/ipython

CHANGELOG.md

@@ -10,6 +10,7 @@
 ## 2112.4 (Tuesday 14th December 2021)
 
 * Fixed more issues with the `depend.mk` rule.
+* Added a `fslipython` wrapper script for `$FSLDIR/bin/ipython`.
 
 
 ## 2112.3 (Monday 13th December 2021)