Building tape type machinery -- common ttype_lookup routine

 - Working on ttype_lookup in cv_lib.py
 - Change cv prefix from 'cv' to 'cvv' so cv_lib does not match
 - Added test to detect duplicate functions
 - Eliminate duplicate functions (cv_popcart, cv_addcart,
   test_interpolation_{fail,ok}, test_addone, etc)

Change-Id: Icbebc6d6e72f0367726b18c708e314480822493d
Working on tape type lookup

 - fleshed out cv.cvv_ttype_lookup, cv_lib.ttype_lookup
 - new cv_lib.ttype_cart_lookup -- retrieve type and subtype numbers
   for a specific cartridge
 - new cv_lib.ttype_map_desc -- convert type and subtype number into a
   string media description
 - new util.lsp_parse -- take the output from an hsi 'ls -P' command
   and extract 1) the item type ('f' or 'd'), 2) the item name, 3) the
   cartridge if any, and 4) the cos if any. These are returned as a
   tuple.

Change-Id: I3b354263246d663ea27b239c653f67e6bef00848