[prototype] added prototype version of mqtt asynchronious api and processing
[feat] improvements of the design
[feature] added logic layer for mqtt processing

This will be responsible for the generic decision on top of the mqtt protocol
It will also be responsible for calling the user logic function that will be informed
about the processing results.
[refac] modified event dispatcher so handlers are easier to use
[refac] switched event dispatcher to use *.h and *.c files

In order to minimize the size of the build
[refac] splited xi_heap and xi_static_vector onto *.h and *.c
[tidy] cleaninig the way that the heap is defined and used

* required to eliminate the void* from the heap definition
[refac] changed the heap and dispatcher relation in order to use stack allocation

over the heap
[refac] final improvement getting rid of heap allocation in case of dispatcher through continuations
[feat][wip] compilable version of the xively with

the new layer communication system based on the event dispatcher
next step will fix all the warnings and bugs and test the publish/subscribe
functionality against the local server
[feat] new calling convention implemented

now xively uses the dispatcher in order to call each layer method
this however will not work with the rest of the non blocking api
that has been used so far, to make it compatible requires further
refactorization which will be done upon the final phase of that current
story
[feat] asynch socket connection working on event dispatcher

still inperfect with a lots of warnings, but works with the asynch posix layer
and mqtt logic layer, now the users callback is called upon success or error in
connection
[fix] fixed unit tests after refactorization of update fd states function
[feat] added some code beautifilizers and simplifiers

now the handle instances ( always named handle so don't forget to put them in {} )
are easier to create and fill with the data
[refac] replaced handle creation with macro

that code contains one small issue but we can solve it later
after the mqtt starts to work
[refac] adjustments to the dispatcher interface

removed things that were outdated, cleaned the interface
simplified and made it more unified across alll parts of the system
[refac][fix] refactorizes the layer interface and updates the layers implementation

In addition it also fixes many compilation warnings and makes
the unit tests compilable and runnable
[fix] fixes most of the anoying compilation warning
[fix] fixed wrong context usage that caused sigseg
[feature] reorganized the select usage so that programm won't spend 100% in main loop

which will help the power usage