Add .swp files to .gitignore

Ignore all swp files from vim. Add *.swp to .gitignore
Add specific error messages inside each validator

Add messages for each validation error in forms.py
Modify template to display specific error messages

Modify block in contact.html to receive and display
specific validation error messages.

Before it was with get_flash_messages(), now it is
with four blocks (one per field) and using the error
attribute of each form field: form.<field>.errors

<field>: name, email, subject, message
Fix flash messages div width

Change width from 200px to 400px to be as wide as the form fields.

Some messages were too long for the previuos width.