Automate version generation

Version is now generated automatically based on git tags.
Both cases are handled: building from git tree and building tarball downloaded from github.

Works for qmake and cmake

cmake/modules/GenerateVersionHeader.cmake

@@ -0,0 +1,28 @@
+find_package(Git)
+
+if(GIT_EXECUTABLE)
+  # Generate a git-describe version string from Git repository tags
+  execute_process(
+    COMMAND ${GIT_EXECUTABLE} describe --tags --dirty
+    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+    OUTPUT_VARIABLE GIT_DESCRIBE_VERSION
+    RESULT_VARIABLE GIT_DESCRIBE_ERROR_CODE
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+  if(NOT GIT_DESCRIBE_ERROR_CODE)
+    set(GIT_VERSION ${GIT_DESCRIBE_VERSION})
+  endif()
+endif()
+
+# Final fallback: Just use a bogus version string that is semantically older
+# than anything else and spit out a warning to the developer.
+if(NOT DEFINED GIT_VERSION)
+  set(GIT_VERSION 0.0.0-unknown)
+  message(WARNING "Failed to determine version from Git tags. Using default version \"${GIT_VERSION}\".")
+endif()
+
+configure_file(
+  ${CMAKE_SOURCE_DIR}/limereport/version.h.in
+  ${CMAKE_BINARY_DIR}/limereport/version.h
+  @ONLY)
+