Fixed timestamps

Now gets timestamps from socket,
instead for current time when `recv` returns.
Optimized `isoblued` function for reading ISOBUS

No longer repeatedly recreates a series of identical structures,
now just makes them once and reuses them.
Optimized writing to buffer, changed protocol
Added options to `can_stress` tool

* Specify data length of CAN frames sent
* Specify finite number of CAN frames to send
Fixed spurious newlines in `isoblue_dummy` output
Minor fixes to `ring_buf`
Minor optimization of ISOBUS module's rx callback
Fixes to ISOBUS socket options

* `getsockopts` now works for filters
* added support for enabling/disabling DA ancillary data
Merge pull request #11 from awlayton/master

Version Used in October 29 2013 Data Logging