Refactor the alternate platform code in the client

[romw]

• Adjust things so that multiple alternate platforms can exist for and platform.
• Move all detection code to it's own file since it'll probably sprawl like host_info.C

[romw]

(In [12531]) - fixes #154:

• refactored the alternate platform mechinism so that we can support multiple alternate platforms.
• moved everything to cs_platforms.C since we expect the kind of sprawl that is in host_info.C on the *nix environments.

• Clean up some warnings

client/

acct_setup.C client_state.C, .h client_types.h cs_platforms.C (Added) cs_scheduler.C cs_statefile.C http_curl.C

lib/

str_util.h