Some unit attributes in XML have non-ASCII space characters

[Steve Loveless]

Some unit names in XML have non-ASCII space characters, and in some cases mix ASCII and non-ASCII space characters. The use of non-ASCII space characters seems incorrect (and can lead to unexpected behavior when dealing with the text). The following contain such:

In name:

• "Queen Anne's wine gallon" (first space is non-ASCII)
• "calorie at 15 °C" (space after the 15)
• "calorie at 20 °C" (space after the 20)
• "British thermal unit at 39 °F" (space after the 39)
• "British thermal unit at 59 °F" (space after the 59)
• "British thermal unit at 60 °F" (space after the 60)

In printSymbol:

• "m H_<r>2</r>O"
• "m Hg"
• "in H_<r>2</r>O"
• "in Hg"