add bloom_filter module

See the comment in bloom_filter.h for info on what a Bloom filter is. I plan to
use this in the IVS tcam module, as well as to replace an existing open-coded
Bloom filter in the IVS upcall processing code.
Merge into master from pull request #23:
add bloom_filter module (https://github.com/floodlight/bigcode/pull/23)
bighash: add optional automatic bucket growth

This is enable by passing BIGHASH_AUTOGROW to create or init. I saw a nice
performance improvement in the TCAM module benchmarks when I added the auto
resize feature there, probably due to better cache locality. I didn't see any
performance change when I tried running a similar benchmark with bighash.

The hairy bighash_grow function is copied from the IVS TCAM module.
Modify the iof_init() return value to indicate whether the IOF was
initialized or inherited. This is required to determine when it is
safe to initialize the IOF settings to custom values.
Merge into master from pull request #25:
iof_init() enhancement (https://github.com/floodlight/bigcode/pull/25)
Allow NULL to specify no formatting for pop-scope.
Merge into master from pull request #26:
Allow NULL to specify no formatting for pop-scope. (https://github.com/floodlight/bigcode/pull/26)
cjson_util module

Utility modules for parsing multilevel keys and validated datatypes.
Lifted and packaged from Indigo's configuration manager.
Remove incorrect comments.
Use aim_zmalloc().
Fix headers.
The lookup_path__ code can now safely mutate the input path directly.
Merge into master from pull request #27:
cjson_util module (https://github.com/floodlight/bigcode/pull/27)
Add file parsing support.
Merge into master from pull request #28:
Add file parsing support. (https://github.com/floodlight/bigcode/pull/28)
BigHash: fix autogrow flag
Merge into master from pull request #24:
bighash: add optional automatic bucket growth (https://github.com/floodlight/bigcode/pull/24)
Allow a hexadecimal value to be specified as a string field and retreived as an integer.
Values specified in this way must start with 0x or 0X.
Merge into master from pull request #29:
Allow hexadecimal integer formats.  (https://github.com/floodlight/bigcode/pull/29)
bighash: fix pedantic warnings

GCC complained about these when using "std=c99 -pedantic-errors -Wextra".