v20190818-142717_6609ad3: Implemented gameboy audio channels 3 and 4

Note that both 7 and 15 bit noise are currently emulated using
the ds noise channels (=15 bit and slightly different) so it
does not sound completely like it should yet.

v20190816-143437_c5a2384

Improved the way timers for direct sound are handled

v20190707-130214_916020e: Only restore shadow regs on bmp->text transition, added general patch…

… for sound mixer used in many games

v20190705-214238_53b7cce: Add support for vram mirrors

Fixes the text in The Legend of Spyro - A New Beginning

v20190705-162556_32ce43a: Update azure-pipelines.yml for Azure Pipelines

Add the CURRENT_DATE variable

commit_8ad384dba2f44ea17c5356d5e018757db7b7dfff: Don't serve hblank irqs during non-gba scanlines

Fixes the Wario Land 4 portal freeze and the Metroid Fusion intro slideshow bug

commit_5abecadd6c838c668dead818f5947513e04f851d: Improved bitmap bg support

Fixes the contra title screen, partially the advance wars intro, Madden NFL
Note that bitmap bg transforms are currently not supported

commit_5b06bb4bd12d8fe12574b0564e0ce0fb7fb02760: Changed dma behavior on invalid addresses again, still not completely…

… correct though

Fixes Dancing Sword - Senkou [J]

commit_e59219891e31d3d30b248b4c6a8bb9289b4d4b80: Set up CI with Azure Pipelines (#60)

* Set up CI with Azure Pipelines

[skip ci]

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update Makefile

* Update Makefile

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

commit_03f86467974caba8ae6c4463b5b5d42ad49ab826

Optimized the abort handler a little more