Remove fontstash library

This library is unused and unmaintained by upstream.

LICENSE

@@ -30,7 +30,6 @@ GPL-2.0-or-later terms, however there are some exceptions:
    - decoders/dr_flac.h, dr_mp3.h, and dr_wav.h: Public Domain or MIT
    - decoders/xxhash.h: BSD 2-Clause
    - enet: MIT
-   - fontstash: Zlib
    - ghc: MIT
    - iir1: MIT
    - loguru: Public Domain

vs/dosbox.vcxproj

@@ -906,7 +906,6 @@ IF %ERRORLEVEL% LSS 8 SET ERRORLEVEL = 0</Command>
     <ClInclude Include="..\src\libs\decoders\stb.h" />
     <ClInclude Include="..\src\libs\decoders\stb_vorbis.h" />
     <ClInclude Include="..\src\libs\decoders\xxhash.h" />
-    <ClInclude Include="..\src\libs\fontstash\fontstash.h" />
     <ClInclude Include="..\src\libs\manymouse\manymouse.h" />
     <ClInclude Include="..\src\libs\mverb\MVerb.h" />
     <ClInclude Include="..\src\libs\nuked\opl3.h" />

vs/dosbox.vcxproj.filters

@@ -1443,9 +1443,6 @@
     <ClInclude Include="..\src\libs\mverb\MVerb.h">
       <Filter>src\libs\mverb</Filter>
     </ClInclude>
-    <ClInclude Include="..\src\libs\fontstash\fontstash.h">
-      <Filter>src\libs\fontstash</Filter>
-    </ClInclude>
     <ClInclude Include="..\src\libs\stb_truetype\stb_truetype.h">
       <Filter>src\libs\stb_truetype</Filter>
     </ClInclude>
@@ -1531,9 +1528,6 @@
     <Filter Include="src\libs\decoders">
       <UniqueIdentifier>{d49f3a50-e4ed-4da7-a530-eeefef580e9b}</UniqueIdentifier>
     </Filter>
-    <Filter Include="src\libs\fontstash">
-      <UniqueIdentifier>{5f937800-dd4d-4ab6-8874-a12f1286102a}</UniqueIdentifier>
-    </Filter>
     <Filter Include="src\libs\mverb">
       <UniqueIdentifier>{8804de8e-c30a-4d93-b2b4-1c1634fd97b7}</UniqueIdentifier>
     </Filter>