* Enhanced http api return codes on error
* added http api tests
* tested mt routing in routing.router
* Documentation for ja-http protocol: sending & receiving SMS
* Completed SMS delivery flows for MT and MO
Files added related to previous commit
Added a description on how to read the documentation
README.md correction of fenced code blocks markdown
Work done:
* Sending SMS-MT with DLR request
* Added redis client to track message IDs for DLR delivery
* dlrThrower just like deliverSmThrower
* smpp.pdu and smpp.twisted projects are now bundled in vendor/ folder, local modifications are needed there
Forgot to add the updated files in last commit, so here they are
Last commits were focusing on getting SMS-MT working through http api with multi-level DLR callbacking, many impacts and some fonctional regressions occured in other modules, so this commit has fixed almost* all of these, the unittest compiles with no problems*

(*): The modification of endOutboundTransaction in smpp.twisted.protocol consisting of handling errors in response of a SubmitSm as a normal callback has impacts on the LongSubmitSm, the following tests are no more valid:
 - jasmin.protocols.smpp.test.test_smpp_client.LongSubmitSmErrorOnSubmitSmTestCase
 - jasmin.protocols.smpp.test.test_smpp_client.SubmitSmIncorrectlyBoundTestCase.test_submit_sm_receiver_failure
It'll be done on next commits
Dont' deleted the queue after testing (using delQueue = True), it takes several seconds to be done and it does not impact any other test
Give the consumer 2 seconds before asserting consumed messages
 * Validate jasmin.protocols.smpp.test.test_smpp_client.LongSubmitSmErrorOnSubmitSmTestCase:
     After modifying the protocol behaviour in endOutboundTransaction (smpp.twisted.protocol) where no more errbacks are called on errors because
     we need to log any error returned from the SMS-C, the long SMS handling behaves differently and must be realigned
 * Validate jasmin.protocols.smpp.test.test_smpp_client.SubmitSmIncorrectlyBoundTestCase.test_submit_sm_receiver_failure which was also impacted as
     the first point
Added tests for:
* Long SubmitSm (through http api)
* Long SubmotSm errors (through http api)
* Incorrectly bound SubmitSm
This fixes #6 and fixes #27
* Documentation coming after
* Some regressions raised in long SubmitSm tests, will be resolved
short_message must be in unicode otherwise, ShortMessageCodingError is raised
Added ShortMessageCodingError
Sending a non-utf8 content through http-api will return a 500 error
* ERRATA: Message content must be already encoded in the desired coding and not in Unicode
* Added GSM0338 encoder/decoder
* Long SMS with SAR options tested in LongSubmitSmUsingSARTestCase
* Sending long SMS using UDH options tested
* Added a new config option: longContentSplit to be set to 'sar' or 'udh' to determine how long message splitting will be done
* Added a new config option: longContentMaxParts, fixing how many concatenations will be done on a long message, the exceeding parts will be ignored
* Added the possibility to switch between SAR or UDH splitting methods in jasmin.cfg (http-api)
* Validated all tests for SAR and UDH splitting of long messages