don't prompt the user if only one toolcahin is present

[shakram02]

Prompting the user for a toolchain when one only is present isn't the best solution in my opinion

[shakram02]

I can't understand the error here, log @KalitaAlexey

$ export PATH=./node_modules/.bin:$PATH
Updating nvm
nvm.install
3.02s$ nvm install 5.0
Downloading and installing node v5.0.0...
Downloading https://nodejs.org/dist/v5.0.0/node-v5.0.0-linux-x64.tar.xz...
Computing checksum with sha256sum
Checksums matched!
Now using node v5.0.0 (npm v3.3.6)
$ node --version
v5.0.0
$ npm --version
3.3.6
$ nvm --version
0.33.11
install.npm
38.89s$ npm install 
npm WARN deprecated gulp-util@3.0.8: gulp-util is deprecated - replace it, following the guidelines at https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5
npm WARN deprecated graceful-fs@3.0.11: please upgrade to graceful-fs 4 for compatibility with current and future versions of Node.js
npm WARN deprecated minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated graceful-fs@1.2.3: please upgrade to graceful-fs 4 for compatibility with current and future versions of Node.js
npm WARN deprecated hoek@2.16.3: The major version is no longer supported. Please update to 4.x or newer
> vscode-rust@0.4.2 postinstall /home/travis/build/editor-rs/vscode-rust
> node ./node_modules/vscode/bin/install
Detected VS Code engine version: ^1.12.0
Found minimal version that qualifies engine range: 1.12.0
Fetching vscode.d.ts from: https://raw.githubusercontent.com/Microsoft/vscode/1.12.0/src/vs/vscode.d.ts
vscode.d.ts successfully installed!
vscode-rust@0.4.2 /home/travis/build/editor-rs/vscode-rust
...
4.73s$ node node_modules/gulp/bin/gulp.js
[16:42:59] Using gulpfile ~/build/editor-rs/vscode-rust/gulpfile.js
[16:42:59] Starting 'compile'...
[16:42:59] Starting 'tslint'...
[16:43:02] Finished 'tslint' after 3.13 s
node_modules/vscode-languageserver-types/lib/umd/main.d.ts(218,15): error TS1066: In ambient enum declarations member initializer must be constant expression.
node_modules/vscode-languageserver-types/lib/umd/main.d.ts(222,15): error TS1066: In ambient enum declarations member initializer must be constant expression.
node_modules/vscode-languageserver-types/lib/umd/main.d.ts(226,14): error TS1066: In ambient enum declarations member initializer must be constant expression.
[16:43:03] 'compile' errored after 4.06 s
[16:43:03] Error: Command `node ./node_modules/typescript/bin/tsc -p .` failed with exit code 1
    at ChildProcess.exithandler (child_process.js:203:12)
    at emitTwo (events.js:87:13)
    at ChildProcess.emit (events.js:172:7)
    at maybeClose (internal/child_process.js:818:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:211:5)
The command "node node_modules/gulp/bin/gulp.js" exited with 1.
Done. Your build exited with 1.