Basic UI & functionality for login, logout, change pwd

[kunfang98927]

Implement requirements in #84, including:

• login (using email address and password)
• change password
• logout
• register (very basic one)

A superuser account for debugging:

• username: fangk3740@gmail.com
• password: monalisa98927

[dchiller]

Good stuff!!! Just a few questions.

[dchiller]

Closes #84