This update boosts the performance of the jsonFormatString function.

This update boosts the performance of the jsonFormatString function.

1. Replaced the old _tabs function, which required the construction and
destruction of a growing_buffer, with a new append_indentation function,
which adds white space to an existing growing_buffer.  This change
eliminates a passel of mallocs and frees.

2. Removed the call to strlen() from the loop condition.

3. Replaced calls to buffer_fadd(), a fairly slow function, with calls
to OSRF_BUFFER_ADD_CHAR() and append_indentation().  Also: replaced a
call to buffer_add_char with the corresponding macro.

4. Eliminated a harmless but wasteful bug that sometimes added
indentation to the end of a line.

In my benchmarking, using a moderately complex JSON string 201
characters long, the new version was seven times as fast as the old.

git-svn-id: svn://svn.open-ils.org/OpenSRF/trunk@1571 9efc2488-bf62-4759-914b-345cdb29e865