edify extensions for OTA package installation, part 2

Adds more edify functions for OTAs:

  is_mounted getprop apply_patch apply_patch_check apply_patch_space
  write_raw_image write_firmware_image package_extract_file

This allows us to install radios, hboots, boot images, and install
incremental OTA packages.

Fixes a couple of dumb bugs in edify itself:

  - we were doubling the size of the function table each time it was
    *not* full, rather than each time it was full

  - "no such function" errors weren't visible to the parser, so they
    didn't prevent execution of the script.