update help and documentation

- update usage.md
- hpdate help output

doc/usage.md

@@ -33,6 +33,7 @@ Usage: xmr-stak [OPTION]...
 
   -h, --help            show this help
   -v, --version         show version number
+  -V, --version-long  show long version number
   -c, --config FILE     common miner configuration file
   --currency NAME       currency to mine: monero or aeon
   --noCPU               disable the CPU miner backend

xmrstak/cli/cli-miner.cpp

@@ -64,6 +64,7 @@ void help()
 	cout<<" "<<endl;
 	cout<<"  -h, --help            show this help"<<endl;
 	cout<<"  -v, --version         show version number"<<endl;
+	cout<<"  -V, --version-long    show long version number"<<endl;
 	cout<<"  -c, --config FILE     common miner configuration file"<<endl;
 #if (!defined(CONF_NO_AEON)) && (!defined(CONF_NO_MONERO))
 	cout<<"  --currency NAME       currency to mine: monero or aeon"<<endl;