DGEngine v0.3.0

Release for Windows

now requires a C++17 compiler.

- add automap code
- add FFmpeg4 support
- add gamma shader
- add horizontal/vertical offset to StringText (SFML 2.5.0)
- add if.regex condition
- add min/max value to InputText
- add multiple if condition action (ex: if x == 1 and y == 2)
- add new game actions
- add new scancodes to keyboard parser
- add palette support to BitmapFont
- allow setting action for any key press
- allow unmounting folders from physfs search path
- changed elapsed time code to process more steps in regards to the current fps limit
- fix blurry level when using odd window size by forcing level view to be even in size
- fully implement load/save game
- initial Spell implementation
- make add/remove gold code generic for all items that have the quantity/capacity properties
- refactor game object query syntax
- refactor getVar*
- refactor level drawing to support multiple layers (for automap)
- refactor Namer into Classifier
- refactor replaceVars to replace vars between || instead of between %% to avoid conflicts with queries
- refactor sfeMovie
- remane val to value
- remove support for old PhysFS
- replace captureInputEvents bool with InputEvent in Button/Level
- replace regex search with string::find
- replace string conversions with C++17's charconv
- require SFML 2.5
- update tileset generation code
- use string_view where appropriate

- update gamefiles
- add F1-F8 keyboard actions to add/remove gold, life, mana, experience (for testing purposes)
- add some initial quests (poisoned water, ogden's sign, farmer's orchard, etc)
- add all default levels (Diablo + Hellfire)
- add automap for all level types + flare

In Hellfire, to enter the crypt, drop the cathedral map near the church tomb. To enter the hive, talk to lester after reaching level 15 - press F7/F8 to change experience (and level).

Note: This is a work in progress. Some things aren't perfect and that's known.
Delete previous saves to avoid errors caused by changes.