* fix imap uid fetching:

* fix imap uid fetching:
  - imap_strip_headers() : fix loading of the line from the buffer
  - imap_strip_headers() : split evaluation for headers_not/headers so we can more easily determine and abort if we want to print the header
  - imap_strip_headers() : if ptr IS StrBufNotNULL we're done reading headers
  - imap_fetch_body() : partial has to be a StrBuf too if its source is; adjust processing accordingly