Update cygwin-build.txt

Changed line 61 to "git clone git://github.com/sgminer-dev/sgminer.git" (Updated to the new address "sgminer-dev" instead of "veox", and changed to "git://" instead of "git@" because it is way easier for newbies to download it that way).

Also added a warning at line 75 that users MUST download the ADL_SDK version 6.0 because v7.0 won't work with SGMiner 4.2.2

doc/cygwin-build.txt

@@ -58,7 +58,7 @@ files.
 You've probably already done this, but this can be done with git or with a zip
 file. With git:
     $ cd
-    $ git clone git@github.com:veox/sgminer.git
+    $ git clone git://github.com/sgminer-dev/sgminer.git
 
 With a zip file:
     $ cd
@@ -70,7 +70,12 @@ With a zip file:
 * Install AMD ADL SDK, latest version (only if you want GPU monitoring)        *
 ********************************************************************************
 Note: You do not need to install the AMD ADL SDK if you are only using Nvidia
-GPUs. Go to this URL:
+GPUs.
+
+Warning: Also take note that the latest AMD ADL SDK 7.0 won't work with SGMiner 4.2.2,
+you MUST download and use the version 6.0. This may change with later version of SGMiner.
+
+Go to this URL:
 http://developer.amd.com/tools-and-sdks/graphics-development/display-library-adl-sdk/
 Download and unzip the file you downloaded:
     $ cd ~/sgminer