GitLab

* moved DataWidth from top axi to Axi4/Axi4Lite objects
* cleaned generators, adopted new naming structure
* implemented generators for arbitrary register files
* master actions improved, simpler constructors
* master actions can be automatically generated from register file
* need to clean up the namespaces etc. - gotten really messy

*  split into subpackages axi4 and axi4lite
*  moved each module into its subpackage
*  shortened names by removing Axi-prefixes wherever possible
*  moved Configs and IOs into corresponding companion object
*  replaced some printlns/printfs with Logging facilities

* moved config params into sealed case class
* unified constructors to use new config object
* added companion object for convenience constructors (backward
  compatible)
* changed constructor calls in unit tests accordingly

* considering the significant delays for real-world rw access
  to memory, AxiSlaveModel should have optional delays to sim
  that behavior
* extracted config to AxiSlaveModelConfiguration class
* adapted existing unit test suites
* bugfix in Axi2AxiSuite: afa now waits for writes to finish

* now has single FIFO of configurable size
* burst size is configurable separately
* burst is started as soon as burstSize is exceeded in buffer
* decided against even more aggressive mode of starting immediately,
  since that would likely be detrimental to system performance
* adapted and verified all unit tests

* new test suite: uses both FifoAxiAdapter and AxiFifoAdapter to
  validate a full roundtrip on a AxiSlaveModel
* most comprehensive test