improve scss compile performance

Now only scss-compile and css-lint the modified file.
fix #1469 - recreating deleted project
Merge pull request #127 from taigaio/bug/1469/reacreating-deleted-project-breaks

fix #1469 - recreating deleted project
Memberlist list fluid layout fix
Merge pull request #126 from taigaio/bug/1452/memberlist-layout

Memberlist list fluid layout fix
Merge pull request #124 from taigaio/bug/1387/sass-compile-performance

improve scss compile performance
Fixed typo
fix styles join
fix #1472
Add attachment limit size information on avatar and attachments
Catch errors with heavy files and show info messages about the maximum size allowed.
Update CHANGELOG.md
Fix CSS errors in linter
fix #1483
Merge pull request #129 from taigaio/bug/1483/wysiwyg-lists

fix issue #1483: wysiwyg lists error
US/1396 - extra text for inviting users
Minor UX and style fixes in add members lightbox
Updating changelog
Fix placeholder
Merge pull request #128 from taigaio/us/1396/extra-text-for-inviting-users

Us/1396/extra text for inviting users