Ignore crappy unknown properties with illegal syntax (see issue #118)

CONTRIBUTING.md

@@ -14,24 +14,26 @@ have found a bug or if you want to request some enhancement, please:
 2. Search the Web for the problem, maybe ask competent friends or in forums.
 3. Browse through the [open issues](https://github.com/rfc2822/davdroid/issues). You can
    also search the issues in the search field on top of the page. Please have a look
-   into the closed issues, too, because many requests have already been handled (and can''t/won''t
+   into the closed issues, too, because many requests have already been handled (and can't/won't
    be fixed, for instance).
 4. **[Fetch verbose logs](https://github.com/rfc2822/davdroid/wiki/How-to-view-the-logs) and prepare
    them. Remove `Authorization: Basic xxxxxx` headers and other private data.** Extracting the
-   logs may be cumbersome work in the first time, but it''s absolutely necessary in order to
+   logs may be cumbersome work in the first time, but it's absolutely necessary in order to
    handle your issue.
-5. Create a new issue, containing
+5. [Create a new issue](https://github.com/rfc2822/davdroid/issues/new), containing
    * a useful summary of the problem ("Crash when syncing contacts with large photos" instead of "CRASH PLEASE HELP"),
    * your DAVdroid version and source ("DAVdroid 0.5.10 from F-Droid"),
    * your Android version and device model ("Samsung Galaxy S2 running Android 4.4.2 (CyanogenMod 11-20140504-SNAPSHOT-M6-i9100)"),
    * your CalDAV/CardDAV server software, version and hosting information ("OwnCloud 6, hosted on virtual server"),
+   * a problem description, including **instructions on how to reproduce the problem** (we need to
+     reproduce the problem before we can fix it!),
    * **verbose logs including the network traffic** (see step before). Enquote the logs with three backticks ```
      before and after, or post them onto http://gist.github.com and provide a link.
 
 
 ## Pull requests
 
-We''re very happy about pull requests for
+We're very happy about pull requests for
 
 * source code,
 * documentation,
@@ -42,11 +44,11 @@ corresponding issue before because will only merge pull requests that
 
 * match our product goals,
 * have the necessary code quality,
-* don''t interfere with other near-term future development.
+* don't interfere with other near-term future development.
 
 However, feel free to fork the repository and do your changes anyway
-(that''s why it''s open-source). Just don''t expect your strategic changes to be
-merged if there''s no consensus in the issue before.
+(that's why it's open-source). Just don't expect your strategic changes to be
+merged if there's no consensus in the issue before.
 
 
 ## Donations

src/at/bitfire/davdroid/resource/Contact.java

@@ -264,9 +264,11 @@ public class Contact extends Resource {
 		vcard.removeProperties(Source.class);
 		// store all remaining properties into unknownProperties
 		if (!vcard.getProperties().isEmpty() || !vcard.getExtendedProperties().isEmpty())
-			unknownProperties = vcard.write();
-		else
-			unknownProperties = null;
+			try {
+				unknownProperties = vcard.write();
+			} catch(Exception e) {
+				Log.w(TAG, "Couldn't store unknown properties (maybe illegal syntax), dropping them");
+			}
 	}