Modify logic for URL determination in YLContextualMenuManager.m

Originally the text needs two or more dot-seperated components to be a URL
Now it needs two or more NON-EMPTY dot-seperated components

Also extract URL determining logic into a category method of NSString
Combine multi-line URL joining logic

Use _extractLongURLFromString to join a multi-line URL
Also add \n into component seperating character set
Enhance URL parsing in NSString category method

"...", "xxx..xxx", ".xxx" or "xxx." will not be considered as URL.
None of the component strings seperated by '.' should be empty for a string to
be a URL.
Improve prefix-completion

Add "http://" only if the string does not have any of the known protocol prefixes
Prefix parsing and auto completion is moved to an NSString category method
Add prefix UJ to category and category methods
Fix compile warnings

* Add casting to [site address] to supress warning(s) in connectToSite: in
  YLConnection
* Let YLConnection use NSStreamDelegate protocol to supress warning(s) about
  delegate methods
YLImagePreviewer.h comforms to NSWindowDelegate

Fix warning
Minor code formatting change
Merge branch 'url-open'
When cmd is pressed, do not open link

If cmd was pressed, the cursor was moved in mouseDown, and link opened in mouseUp.
Change this to ignore mouseUp open link if cmd is pressed.
Change image viewer switch to shift
Map CMD Up/Down/Left/Right to PgUp/PgDn/Home/End

Also changed the hotkey of "switch to previous/next tab" from CMD Left/Right to OPT.
Add Browser fallback when URL can't be opened as image
Short URL look-back mechanism to better detecting images
Merge pull request #10 from uranusjr/master

- 把 Cmd 上下左右對應到 PgUp/PgDn/Home/End
- 增加短網址反查, 即使是縮過網址的圖片也能用 image previewer 開
- 稍微改善對 URL 的判斷, 不會把 "..." 之類的字串判斷成網址
Fix corrupt encoding.
Upgrade project file to Xcode 4.4
Fix for the unintended blue border.
Revert the switching-tab keyboard shortcut to Cmd+Left/Right
Replace the deprecated NSImage compositeTo… method to drawAt… method.