Enhance GMail Basic HTML with keyboard shortcuts
As of
A simple script that adds keyboard shortcuts to the HTML-only version of Gmail.
```
gi Go to inbox
gk Go to first label inbox
t Toggle checkbox of current mail
mr Mark checked mails as read
mu Mark checked mails as unread
k Navigate up in mail list (shift twice as fast)
j Navigate down in mail list
h Go to older mail(s)
l Go to newer mail(s)
Enter Open mail
r Reload
b Back
n New mail
```
