Enable Release build in PKGBUILD and also use this configuration in the compilation guide

AUR/PKGBUILD

@@ -21,7 +21,7 @@ pkgver () {
 
 build () {
 	cd "$srcdir/$pkgname-git"
-	cmake .
+	cmake -DCMAKE_BUILD_TYPE=Release .
 	make
 }
 

doxygen/compilation.dox

@@ -37,16 +37,16 @@ Development is done with the following library versions:
 Go to the build directory you want to compile in. This may be the gds-render project root.
 Execute
 @code
- cmake <Path to gds-render root>
+ cmake -DCMAKE_BUILD_TYPE=Release <Path to gds-render root>
 @endcode
 
-Cmake will check the dependencies. Once cmake has finished. Type
+for a build in release configuartion. Use `-DCMAKE_BUILD_TYPE=Debug` for debugging. Cmake will check the dependencies.
 
+Once cmake has finished, type
 @code
  make
 @endcode
-
-in order to build the program and 
+to build the program and 
 
 @code
  make documentation