Set the System Identifier as a unique string.
Adding support for HTML5 form validation to selector for countries.
Correcting comments.
Merge pull request #1666 from shefik/selector_countries

Adding support for HTML5 form validation to selector for countries.
Modifying var to output a 32-character hexadecimal number.
Merge pull request #1665 from shefik/unique_identifier

This PR was merged into zikula:1.4 branch.

Discussion
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Set the System Identifier as a unique string.

Use Case: At installation, it is useful to set a unique identifier (as a system var) that can be used to identify the system. This system var can be then to be used as string mapped to third-party services.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| Refs tickets  | -
| License       | MIT
| Doc PR        | -

Commits
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aedf2da8ca7487fb714ce725743aa4694eb283c4 Set the System Identifier as a unique string. shefik
5d7ce0a5c6861eee447b3347baaf0796f6d4c04f Modifying var to output a 32-character hexadecimal number. shefik
[1.4 Users] Updated Api_registration for sendpass

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | -
| Fixed tickets | -
| Refs tickets  | -
| License       | MIT
| Doc PR        | -

When another module wants to use the Users_registration Api and the registerNewUser method you cannot use the sendpass functionality. When a webshop (e.g. zwebstore) with automatic account creation based on user data with a generated password wants to send the generated password to the new account then this update is needed. Otherwise you cannot send the password. 

Automatic account creation saves 1 extra step in customer approach in webshops. And 1 extra step can be one too many in these fast times.
Merge pull request #1670 from espaan/patch-5

[1.4 Users] Updated Api_registration for sendpass