separate from the input filter mode type.

We also no longer look at readbytes to determine the method of
filter operation.  This makes the use of filters more obvious and
allows a wider range of options for input filters modes.

To start with, the new input filter modes are:

AP_MODE_READBYTES (no more than *readbytes returned)
AP_MODE_GETLINE (old *readbytes == 0 case)
AP_MODE_EATCRLF (old AP_MODE_PEEK)
AP_MODE_SPECULATIVE (will be used in a future ap_getline rewrite)
AP_MODE_EXHAUSTIVE (old *readbytes == -1 case)
AP_MODE_INIT (special case for NNTP over SSL)

The block parameter is an apr_read_type_e: APR_BLOCK_READ, APR_NONBLOCK_READ

This also allows cleanup of mod_ssl's handling in the getline case.

Reviewed by:	Ryan Bloom (concept), Greg Stein (concept)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@92928 13f79535-47bb-0310-9956-ffa450edef68