Make 'bscr test' default to py.test

 - If py.test is not available, we fall back to green, then nosetests.
 - User can specify '-t py.test', '-t green', or '-t nose' to indicate
   which test runner to use.
Remove coverage warning from subproc output

 - Added testhelp.rm_cov_warn()
 - Call testhelp.rm_cov_warn() where needed
Test logging in py.test

 - py.test ... --logpath <path> ...
Add coverage support

 - py.test ... --cov bscr ...
Paging support for 'bscr readme'

 - Using pager module
 - Do something reasonable if the pager module is not available
 - Replace 'make upgrade' with 'make up'
Release 2014.0913