Add a function to the base_type class for providing the option nafunc
Boilerplate for option[string]
Add a type pattern matching routine
Eliminate the separate errmode parameter in assignment, just use ectx
Add string to ?T assignment kernels so some NA tokens convert properly
Fix error in option type w.r.t. expression types
Some formatting changes
Change the set_utf8_string API on base_string

Will move this up to base_type as a common way to deal with strings
from types
Got the basics of the option[date/time/datetime] types working
Merge pull request #55 from mwiebe/more_option

More work on the option type
Tweak nd::empty<T>() so thate nd::empty<float[3][4]>() works
Split test_elwise.cpp into 6 files to try and reduce memory usage
Split up elwise.hpp into pieces to try and reduce compile memory usage
Comment out lambda-function example
Try isfinite fix for gcc 4.4 as well
Reduce the # of generated elwise variants
Simplify the ckernels being used, make unary just use expr
Merge pull request #58 from mwiebe/exec

Simplify the ckernels being used, make unary just use expr