Fixed issue with pow grad function trying to evalutate log at 0. Issue 1780
Added unit test.
Note: issue still occurs in debugmode.
Fixed error message for scan op dimension mismatch
Added equal and notEqual operation between sparse matrices
Added support for sparse-dense matrices comparison, tests and updated documentation.
Added scipy version check
Add a list store executed node order
Modified version check
Renamed function eq and neq
Fixed comment
Added le, lt, ge, gt and associated test cases
Added documentation
made fixes and tweaks
fixed formatting
Disabled nan/infinity checks for the Pow*Testor.
Fixed version check
Merge pull request #1860 from daemonmaker/issue1780

Issue1780
Merge pull request #1851 from Hengjean/sparseComparisonOp

Added comparisons operators for sparse matrices
Implemented basic typed list
Fixed comments and little formating error
Minor fix to make pickle example more accurate.