201410 rayg entrypoints

- added "viirsmend" entry point after moving condition __main__ code into main()
- fixed case where entering a "naked" GMTCO file with no directory would result in output filenames being created with / on the front
before:
2014-10-21 19:42:58,835 replace_c 94 INFO: Globbing on: /SVM10_npp_d20130929_t0953351_e0954592*noaa_ops.h5
2014-10-21 19:42:58,835 loopfiles 124 WARNING: replace_c couldn't find file to match SVM10_npp_d20130929_t0953351_e0954592_b09960_c20130929161901147997_noaa_ops.h5
after:
2014-10-21 19:43:53,303 replace_c 94 INFO: Globbing on: ./SVM10_npp_d20130929_t0953351_e0954592*noaa_ops.h5
Creating:  ./SVM10_npp_d20130929_t0953351_e0954592_b09960_c20130929161531317021_noaa_ops.mended.h5