Fix -n "User PIN:" mis-print and Token/SmartCard keysize adjust in vars

<b>Fix -n "User PIN:" mis-print</b>
The <code>echo -n</code> dos not work in a vanilla Bourne shell (not linked to bash) and just prints:
<pre>-n User PIN: 
(also a new line is added and the cursor is on the next line)
</pre>
Changed it into using printf which is more consistent between different shells


<b>PKCS11_KEY_SIZE in vars for setting Token/SmartCard key size (1024 or 2048)</b>
Added the <code>PKCS11_KEY_SIZE=1024</code> in the <code>./vars</code> as default value.

Changed the pkitool to use the value from <code>PKCS11_KEY_SIZE</code> for setting the internal priv/pub key size of smart cards and tokens. Old cards only support 1024, newer cards support 2048+ bits internally.

Hope this helps!

Wessel