Renamed "pattern" kind to "symbolic"
Add some tests of the symbolic types
Renamed nd::array.is_empty() to is_null() in libdynd
Merge pull request #79 from mwiebe/funcproto

Funcproto changes corresponding to libdynd PR
Rename the gfunc directory to just func
Start renaming ckernel_deferred to arrfunc
Renamed the ckernel_deferred struct to arrfunc
Rename lift_ckernel_deferred to lift_arrfunc
Rename lift_reduction_ckernel_deferred to lift_reduction_arrfunc
rolling_ckernel_deferred to rolling_arrfunc, take_ckernel_deferred to take_arrfunc
Rename the remaining ckernel_deferred to arrfunc
Merge pull request #80 from mwiebe/arrfunc

Updates corresponding to libdynd arrfunc