Due to Solr bug SOLR-15039, uploading files for indexing can fail if
it uses multipart upload. This changes it to use direct binary upload.
Unfortunately, the direct binary version in PHP curl only supports a
string, so we have to load the file into memory. I added extra code to
restrict the size of files indexed to (memory limit - 100MB), which is
usually 284MB unless configured differently because cron runs under
MEMORY_EXTRA.
sam marshall
cca005b48a