Minor scripting improvements and code cleaning.

* Coding policy fixes in the scripting initialization code missed in my previous commit.
* Remove redundant checks for valid Python library paths in kicadplugins.i.

pcbnew/pcbnew.cpp

@@ -207,7 +207,7 @@ static bool scriptingSetup()
 
 #if defined( __MINGW32__ )
     // force python environment under Windows:
-    const wxString python_us( "python27_us" );
+    const wxString python_us( wxT( "python27_us" ) );
 
     // Build our python path inside kicad
     wxString kipython =  FindKicadFile( python_us + wxT( "/python.exe" ) );
@@ -281,21 +281,21 @@ static bool scriptingSetup()
     wxSetEnv( "PYTHONPATH", pypath );
 
 #else
-    /* Linux-specific setup */
+    // Linux-specific setup
     wxString pypath;
 
     pypath = Pgm().GetExecutablePath() + wxT( "../lib/python2.7/dist-packages" );
 
-    if( !wxIsEmpty( wxGetenv("PYTHONPATH") ) )
-        pypath = wxString( wxGetenv("PYTHONPATH") ) + wxT( ":" ) + pypath;
+    if( !wxIsEmpty( wxGetenv( wxT( "PYTHONPATH" ) ) )
+        pypath = wxString( wxGetenv( wxT( "PYTHONPATH" ) ) ) + wxT( ":" ) + pypath;
 
-    wxSetEnv( "PYTHONPATH", pypath );
+        wxSetEnv( wxT( "PYTHONPATH" ), pypath );
 
     // Add this default search path:
     path_frag = Pgm().GetExecutablePath() + wxT( "../share/kicad/scripting/plugins" );
 #endif
 
-    if( ! pcbnewInitPythonScripting( TO_UTF8( path_frag ) ) )
+    if( !pcbnewInitPythonScripting( TO_UTF8( path_frag ) ) )
     {
         wxLogError( wxT( "pcbnewInitPythonScripting() failed." ) );
         return false;

scripting/kicadplugins.i

@@ -78,17 +78,17 @@ def ReloadPlugins():
             ReloadPlugin(k)
 
 
-def LoadPlugins( plugpath ):
+def LoadPlugins(plugpath):
     import os
     import sys
 
     kicad_path = os.environ.get('KICAD_PATH')
     plugin_directories=[]
 
-    if plugpath and os.path.isdir( plugpath ):
-        plugin_directories.append( plugpath )
+    if plugpath:
+        plugin_directories.append(plugpath)
 
-    if kicad_path and os.path.isdir(kicad_path):
+    if kicad_path:
         plugin_directories.append(os.path.join(kicad_path, 'scripting', 'plugins'))
 
     if sys.platform.startswith('linux'):
@@ -97,8 +97,7 @@ def LoadPlugins( plugpath ):
 
     if sys.platform.startswith('darwin'):
         for singlepath in sys.path:
-            if os.path.isdir( os.path.join( singlepath, 'scripting', 'plugins') ):
-                plugin_directories.append( os.path.join( singlepath, 'scripting', 'plugins') )
+            plugin_directories.append(os.path.join( singlepath, 'scripting', 'plugins'))
 
     for plugins_dir in plugin_directories:
         if not os.path.isdir(plugins_dir):