Code and GUI text cleanup (#926)

* Move int range checkers from options class to common file
* Improve error handling and reporting
* Make some minor improvements to init and test suite
* Fix 'trypewriter' to 'typewriter' typo
* Remove menu path description in dialog help text
* Improve the help text for entries in the Format menu
* Reword a couple of dialog messages

novelwriter/__init__.py

@@ -215,25 +215,25 @@ def main(sysArgs=None):
     errorCode = 0
     if sys.hexversion < 0x030600f0:
         errorData.append(
-            "At least Python 3.6.0 is required, found %s" % CONFIG.verPyString
+            "At least Python 3.6 is required, found %s" % CONFIG.verPyString
         )
-        errorCode |= 4
+        errorCode |= 0x04
     if CONFIG.verQtValue < 50300:
         errorData.append(
             "At least Qt5 version 5.3 is required, found %s" % CONFIG.verQtString
         )
-        errorCode |= 8
+        errorCode |= 0x08
     if CONFIG.verPyQtValue < 50300:
         errorData.append(
             "At least PyQt5 version 5.3 is required, found %s" % CONFIG.verPyQtString
         )
-        errorCode |= 16
+        errorCode |= 0x10
 
     try:
         import lxml  # noqa: F401
     except ImportError:
         errorData.append("Python module 'lxml' is missing")
-        errorCode |= 32
+        errorCode |= 0x20
 
     if errorData:
         errApp = QApplication([])