Current directory check does not work with symbolic links

[OuyeXie]

https://github.com/spullara/mustache.java/blob/a1197f7789b24d694f16dad29f917e9be43f0dc2/compiler/src/main/java/com/github/mustachejava/resolver/FileSystemResolver.java#L45

The line above gets the canonical path of the file and this check will break when "file" is a symbolic link .

My example:

• file abs: /local/asdf/_env/asdf-swit1na.18021267.375759313.1848829265/static-content/templates/asdf.html.mustache
• parent abs: /local/asdf/package/local_1/Generic/asdf/asdf-441.0-0/static-content/templates/asdf html.mustache
• checkRoot abs: /local/asdf/_env/asdf-swit1na.18021267.375759313.1848829265

And under directory: /local/apollo/_env/asdf-swit1na.18021267.375759313.1848829265

• static-content -> ../../package/local_1/Generic/asdf/asdf-441.0-0/static-content

[spullara]

Hmmm. I'll take a look if there is another way to safely check that they aren't escaping the root.