Checking object class rather than its existence before accessing its
properties
Removed check for empty E-Mail account

We are only retrieving existing E-Mail accounts in get_email_accounts()
method so they is need to check for their existence again
Showing only E-Mail account username

Two different E-Mail accounts can't have same username so it is useless to
show IMAP host name along with it
Remove manual override of table columns width

There are causing table to take fix width even if there is lot of extra
space
For example in wp-admin/edit.php?post_type=sf_thread&page=sf_permissions,
status columns takes very small width even insufficient to shows it
content properly
Refactored code to make more readable
Making respondent E-Mail ID starts in same line as its photo in all
threads page

Currently if respondents E-Mail ID is long enough to not fit in line with
respondent photo it leaves the whole line empty moving to next line
completely