[CHANGE] extended version string and corresponding parser in cmake to allow...

[CHANGE] extended version string and corresponding parser in cmake to allow arbitrary tags in the version string.

VERSION

 # OW Version File. This file specifies the version. The line VERSION=X.Y.Z is
-# used and parsed. This file has to be here everytime. The VERSION needs to be
+# used and parsed. This file has to be here every time. The VERSION needs to be
 # set properly or CMake will fail.
 #
 # SYNTAX: The version string always is 1.2.3 with an optional postfix of "+hg1234".
 #         This is useful if building is done by scripts. If you want to automatically
 #         add the correct HG revision, use only +hgX without number.
+#         You can optionally add underscore separated tags. The allowed characters in
+#         these tags are letters and numbers and you must begin with a letter.
+#         See examples below.
 #
 # IMPORTANT: If you modify the file, cmake re-creates the version header. But
 #            it is not able to set all library version. Please re-run cmake if
 #            you change something here.
 #
-# NOTE: do not add a space after #. The current CMake script will fail.
 # Examples:
-#VERSION=1.2.0
-#VERSION=1.2.0+hgX  -> replaces the X with the current revision number
-#VERSUIB=1.2.0+hg1234 -> here, revision number was set by the build scripts for example.
+#   VERSION=1.2.0
+#   VERSION=1.2.0+hgX  -> replaces the X with the current revision number
+#   VERSION=1.2.0+hg1234 -> here, revision number was set by the build scripts for example.
+#   VERSION=1.2.0_RC1_PreRelease_SomeText+hgX -> You can add arbitrary tags to the version string. But be careful. Usually only one tag is useful.
+
+# The current version string:
 VERSION=1.3.0+hgX

tools/cmake/OpenWalnutUtils.cmake

@@ -535,7 +535,7 @@ FUNCTION( GET_VERSION_STRING _version _api_version )
         # Read the version file
         FILE( READ ${OW_VERSION_FILENAME} OW_VERSION_FILE_CONTENT )
         # The first regex will mathc 
-        STRING( REGEX REPLACE ".*[^#]VERSION=([0-9]+\\.[0-9]+\\.[0-9]+(\\+hgX?[0-9]*)?).*" "\\1"  OW_VERSION_FILE  ${OW_VERSION_FILE_CONTENT} ) 
+        STRING( REGEX REPLACE ".*[^#]VERSION=([0-9]+\\.[0-9]+\\.[0-9]+[_a-z,A-Z,0-9]*(\\+hgX?[0-9]*)?).*" "\\1"  OW_VERSION_FILE  ${OW_VERSION_FILE_CONTENT} ) 
         STRING( COMPARE EQUAL ${OW_VERSION_FILE} ${OW_VERSION_FILE_CONTENT}  OW_VERSION_FILE_INVALID )
         IF( OW_VERSION_FILE_INVALID )
             UNSET( OW_VERSION_FILE )