Added file_size and file_content_hex Jinja filters.

Added check if Jinja module exists and appropriate error message to
project generation.

SConscript

@@ -3,7 +3,6 @@ import copy
 import enum
 import glob
 import inspect
-import jinja2
 import json
 import multiprocessing
 import os
@@ -540,6 +539,11 @@ def _target_entry(target_value):
     return target_value[0]
 
 def _generate_project(project_type: str) -> None:
+    try:
+        import jinja2
+    except ImportError:
+        _error(None, 'Project generation requires the jinja2 to be installed.')
+
     source_folder, target_folder = {
         'clion': (os.path.join(_spp_dir.abspath, 'util', 'clion_project_template'), Dir('#.idea').abspath),
         'vscode': (os.path.join(_spp_dir.abspath, 'util', 'vscode_project_template'), Dir('#.vscode').abspath)