XTCE12 — Fix overuse of FixedIntegerValueType in proposal

The FixedIntegerValueType introduced in XTCE 1.2 proposals is quite handy and flexible. In some cases, it was specified where it should not be. Propose to remove it's usage and revert to "long" for the cases of basic size and range specifications.

Propose to undo some of the FixedIntegerValueType uses

This is a useful new type definition in XTCE 1.2 proposals, but slightly overused. In many basic cases of sizing, this causes excess overhead for implementations to need to interpret several forms of integer representation where it is not needed. It is actually clearer to the reader to have just the regular integer base 10 representation.

Propose to re-adjust the complexType "IntegerValueType" by changing the line from:

<element name="FixedValue" type="xtce:FixedIntegerValueType"/>

to

<element name="FixedValue" type="long"/>

Also re-adjust the complexType "IntegerRangeType" by changing the lines from:

<attribute name="minInclusive" type="xtce:FixedIntegerValueType"/>
<attribute name="maxInclusive" type="xtce:FixedIntegerValueType"/>

to

<attribute name="minInclusive" type="long"/>
<attribute name="maxInclusive" type="long"/>

Also re-adjust the complexType "IntegerValueType" by changing the line from:

<element name="FixedValue" type="xtce:FixedIntegerValueType"/>

to

<element name="FixedValue" type="long"/>

Lastly, re-adjust the complexType "IntegerDataType" by changing the line from:

<attribute name="initialValue" type="xtce:FixedIntegerValueType">

to

<attribute name="initialValue" type="long">

Correspondingly, update the documentation element to also reflect the change to @initialValue:

<documentation xml:lang="en">Initial value is always given in calibrated form.</documentation>