Performance optimization in subvolume copy code.

Commented out unused section of subvolume copy. Formerly, this code was
used to detect overlapping subvolume copies, necessary for the buffer
compact operation, but this is no longer done, so it is simply wasting
CPU cycles.
Added more timers throughout ADIOS, with tiered conditional disabling for
efficiency during performance testing.

To enable timers, the macro TIMER_LEVEL must be set to some integer value; higher values
enable progressively fewer timers.
Added PG access messages with conditional compilation (currently disabled),
to determine why transformed reads are being performed somewhat out of order
(can be re-enabled with a #define at the top of read_bp.c).
Fixed a linked list prepend bug. It affected read request queuing order
in the Transport layer, which lead to sub-optimal read order when using
the Transform layer.
Inlined/staticed a few local helper functions for efficiency, hopefully.
Added absolute PG index optimization to whole-PG reads. Previously only
sub-PG reads were so optimized.
Fixed some bugs in the APLOD plugin implementation.
Added a string-based read parameter to the adios_schedule_read function. Also added parsing of this parameter to APLOD.
Modified  sieving in APLOD.

Now, sieving will only be used if numComponents == 1 (in this case, only one seek is required).
Otherwise, the full PG will be read, but only the components specified for the query
(thus, still only one seek is used). This is because it seems seeks are quite expensive, so we
limit them in exchange for a bit of extra data read. In the future, a more complex heuristic
could be used.
Cleaned up ALACRITY write plugin