Update js and json syntatic checkers

vimrc

@@ -65,12 +65,11 @@ let NERDTreeIgnore = ['\.pyc$']
 let g:syntastic_phpcs_disable=1
 let g:syntastic_auto_loc_list=1
 let g:syntastic_stl_format = '[%E{Err: %fe #%e}%B{, }%W{Warn: %fw #%w}]'
-"let g:syntastic_json_checker = "jsonlint"
+let g:syntastic_json_checker = "jsonlint"
 let g:syntastic_scss_checkers = []
 let g:syntastic_css_checkers = []
 let g:syntastic_html_checkers=[]
-"let g:syntastic_javascript_checkers = ['jshint', 'jscs']
-let g:syntastic_javascript_checkers = ['jshint']
+let g:syntastic_javascript_checkers = ['jshint', 'eslint', 'jscs']
 
 " Close all open buffers on entering a window if the only
 " buffer that's left is the NERDTree buffer