Use textP more widely, to avoid array pinning
Rename textP to text

Replace the old text smart constructor with the slightly smarter
one we've had all along that ensures that it doesn't pin its array
if it's empty.
Fix URL
Make developer flag manual-only

This makes the cabal constraint solver's job easier (fewer
combinations to try) and makes it impossible for it to set developer
to True when installing the library.
Merge