Updated composer install instructions
Add check exists before unlink and refactor

Header & Footer file now only removed when option is not null and file exists.

Fixes:
when option['header-html'] or option['footer-html'] is null then
unlink(): No such file or directory
thrown on generate.
Fix isFileHeader/isFileFooter Params

Now passing full options array
CS fixes
Add a possibility to specify the temporary folder
Merge pull request #126 from R2c/master

Add a possibility to specify the temporary folder
Merge pull request #121 from daniel-helpling/master

Add check header and footer not null and exist before unlink
remove only temporary files created by the generator, on destruct
Merge pull request #127 from smatyas/remove-only-temp-files-on-destruct

remove only temporary files created by the generator, on destruct
Merge pull request #118 from philsturgeon/patch-1

Updated composer install instructions
Fix #121

isFileFooter have missed argument
Merge pull request #128 from piotrantosik/master

Fix #121
Update dev branch alias
Merge pull request #129 from piotrantosik/master

Update dev branch alias
Add possibility to pass a cover as html
add documentation
added a newline before the return statement
Missing variable
Merge pull request #130 from krispypen/cover_as_html

Add possibility to pass a cover as html
Merge pull request #131 from aRn0D/constructor

Allowing the possibility to specify env properties for PDF and Image classes