adding command dependency

tests/data/app/expected-info.json

@@ -32,6 +32,20 @@
 					"@value": "sqlite"},
 				"mysql"
 			]
-		}
+		},
+		"command": [
+			{
+				"@attributes" : {
+					"os": "linux"
+				},
+				"@value": "grep"
+			},
+			{
+				"@attributes" : {
+					"os": "windows"
+				},
+				"@value": "notepad.exe"
+			}
+		]
 	}
 }

tests/data/app/valid-info.xml

@@ -25,5 +25,7 @@
 			<database min-version="3.0">sqlite</database>
 			<database>mysql</database>
 		</databases>
+		<command os="linux">grep</command>
+		<command os="windows">notepad.exe</command>
 	</dependencies>
 </info>