Custom symbol support (registry part)

Proposal for the symbol support:
* We can specify a symbol in the appliance via the symbol field (gui
will fallback to default symbol if not internet available)
* Contributor should provide the licence for the symbol

Fix #5

README.rst

@@ -5,7 +5,11 @@ GNS3-registry
     :target: https://travis-ci.org/GNS3/gns3-registry
 
 This is the GNS3 registry where user can share
-appliances configurations.
+appliances configurations and symbols.
+
+Add a new symbol
+################
+Look for examples in the symbols directory.
 
 
 Add a new appliance

appliances/microcore-linux.gns3a

@@ -12,7 +12,8 @@
     "maintainer": "GNS3 Team",
     "maintainer_email": "developers@gns3.net",
     "usage": "Login is tc. sudo work without password",
- 
+    "symbol": "linux_guest.svg",
+
     "qemu": {
         "adapter_type": "e1000",
         "adapters": 1,

check.py

@@ -18,7 +18,7 @@
 import os
 import jsonschema
 import json
-
+import sys
 
 def check_schema(appliance):
     with open('schemas/appliance.json') as f:
@@ -29,10 +29,23 @@ def check_schema(appliance):
         jsonschema.validate(appliance_json, schema)
 
 
+def check_symbol(symbol):
+    licence_file = os.path.join('symbols', symbol.replace('.svg', '.txt'))
+    if not os.path.exists(licence_file):
+        print("Missing licence {} for {}".format(licence_file, symbol))
+        sys.exit(1)
+
+
 def main():
+    print("=> Check appliances")
     for appliance in os.listdir('appliances'):
         print('Check {}'.format(appliance))
         check_schema(appliance)
+    print("=> Check symbols")
+    for symbol in os.listdir('symbols'):
+        if symbol.endswith('.svg'):
+            print('Check {}'.format(symbol))
+            check_symbol(symbol)
 
 if __name__ == '__main__':
     main()

symbols/README.rst

@@ -0,0 +1,11 @@
+Symbols
+*******
+
+This directory contain symbols that you can import in GNS3.
+
+Rules
+=====
+
+* All symbols must be provided as a SVG file
+* A file named symbol.txt should exist and contain symbol licence
+* Try top keep a small file size

symbols/linux_guest.txt

@@ -0,0 +1,10 @@
+Tux:
+https://commons.wikimedia.org/wiki/File:NewTux.svg
+(c) Larry Ewing, Simon Budig und Anja Gerwinsk
+©	The copyright holder of this file, Larry Ewing, allows anyone to use it for any purpose, provided that the copyright holder is properly attributed. Redistribution, derivative work, commercial use, and all other use is permitted.
+Attribution: Larry Ewing
+
+This work is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or any later version. This work is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See version 2 and version 3 of the GNU General Public License for more details.
+
+Computer Background:
+Public Domain Computer from GNS3