Extend sqrtm to StridedMatrix and complex integer matrices.
Make sqrtm more forgiving to singular matrices.
Benchmark tweaks:

* Added pi_sum_vec to Matlab, Julia and R (disabled)
* Tweaked parseint in perf.R
* Added perf.lua by Francesco Abatte (Needs the GSL Shell)
Revert "Revert "remove some O(n^2) algorithms in the front end" [fix #2270]."

This reverts commit 1396f74efdf9a87d7c2658757f8d2b20885f67c1.
try a different implementation of delete-duplicates
Merge branch 'master' into sqrtm
More sqrtm tests.
Revert "try to improve the STDIN as IOStream workaround"

This reverts commit 4e8cabc337b4164b176534a85ffcfcd6578f947f.
Revert "make STDIN an IOStream on linux when the input stream is a file"

This reverts commit 64451781dcba91dc7a5b4884afdd5eb4153d9e41.
perf: Lua corrections and pi_sum_vec in Python (disabled)
perf.lua: fix oversight
perf.R: cache the pi_sum_vec range to match other implementations.
fix #2297
perf.lua: Adding pure Lua variants.
fix #2307
doc/stdlib: add OS_NAME (closes #2218)
beginning the redesign to add immutable types and abstract types with fields.
combine AbstractKind, BitsKind, CompositeKind into DataType
this is a save checkin. the first couple files have been converted.
update array storage for new data types
fix cumsum, #2342
fix #2336, julia-in-comment in emacs mode