fallback to wp-content/uploads if tmp dir is not writable (e.g. shared host)

Hopefully addresses #8
Use WordPress's native `get_temp_dir()`

Will fallback to WP Internal folders if PHP default is not writable.
use wp_filesystem for better compatability
create wp-content dir
try using heckyesmarkdown to prevent parse errors
remind users about zip.so
Merge pull request #13 from jiehanzheng/patch-1

remind users about zip.so
Added CLI exporter.
Added CLI instructions
Merge pull request #17 from ghelleks/master

Add CLI export tool.
add wp-cli command

Conflicts:
	jekyll-export-cli.php
	readme.md
use Markdownify to convert HTML
better WP-CLI, non-WP-CLI-compatability
check if plugin is activated via CLI
Merge pull request #19 from benbalter/wp-cli

Add wp-cli command, props @scribu
Merge branch 'master' of https://github.com/benbalter/wordpress-to-jekyll-exporter into the-return-of-markdownify

Conflicts:
	jekyll-export-cli.php
	jekyll-export.php
	readme.md
resolve merge markup
Reduce memory use by flushing buffers and periodically closing the zipfile
return HTML if Markdownify creates invalid links
Merge pull request #20 from benbalter/the-return-of-markdownify

Use Markdownify to convert HTML