Path attribute should follow common format

[beatngu13]

Paths currently have the following form:

HTML[1]/BODY[1]/A[1]

The path represents the absolute XPath to the corresponding element. According to the XPath specification:

An absolute location path consists of / optionally followed by a relative location path.

Moreover, although the HTML specification says that "tag names are case-insensitive", they typically only consist of lower-case letters.

Therefore, we should start with / and use lower-case letters:

/html[1]/body[1]/a[1]

[enesoezel]

We filter out the path separator here at the beginning of the method. Changing this method could lead to many problems that are not directly apparent. We should discuss that. @beatngu13 @roesslerj

[beatngu13]

Lowercase migrator merged in retest/recheck#180. However, this doesn't address e.g. the leading slash. We should also think about enforcing our desired format in Path.

[beatngu13]

What I also realized and I think this is related: When copying a XPath from Chrome, one gets something like:

/html/body/div[2]

That is, [1] is omitted, so I think it should be optional in our XPath too.