Enable alternative ways for settings passwords (#101)

* Enable alternative ways for settings passwords:
* the environment variable BW_PASSWORD
* prefix the command line argument with "file:" and the password will read from the first line of that file
* prefix the command line argument with "env:" and the password will be read from that environment variable

* Appveyor fixes

* Switch to using command options for password file and password env

* Lowercase options

src/misc/nodeUtils.ts

@@ -1,5 +1,6 @@
 import * as fs from 'fs';
 import * as path from 'path';
+import * as readline from 'readline';
 
 export class NodeUtils {
     static mkdirpSync(targetDir: string, mode = '700', relative = false, relativeDir: string = null) {
@@ -13,4 +14,16 @@ export class NodeUtils {
             return dir;
         }, initialDir);
     }
+    static readFirstLine(fileName: string) {
+        return new Promise<string>((resolve, reject) => {
+            const readStream = fs.createReadStream(fileName, {encoding: 'utf8'});
+            const readInterface = readline.createInterface(readStream);
+            readInterface
+                .on('line', (line) => {
+                    readStream.close();
+                    resolve(line);
+                })
+                .on('error', (err) => reject(err));
+        });
+    }
 }