Support import statements where path if './file.sol'

Fixes https://github.com/chriseth/browser-solidity/issues/108

src/app.js

@@ -723,6 +723,9 @@ var run = function() {
 				if (getFiles().indexOf(fileKey(m)) !== -1) {
 					files[m] = window.localStorage[fileKey(m)];
 					reloop = true;
+				} else if (m.startsWith('./') && getFiles().indexOf(fileKey(m.slice(2))) !== -1) {
+					files[m] = window.localStorage[fileKey(m.slice(2))];
+					reloop = true;
 				} else if (m in cachedRemoteFiles) {
 					files[m] = cachedRemoteFiles[m];
 					reloop = true;