Bug fixes

• when adding image to relationship first check that the generated RID is actually unique #2063 (tpv-ebben)
• Update chart, don't write 'c:overlap' if grouping is 'clustered' #2052 (dfsd534)
• Update Html parser to accept line-height:normal #2041 (joelgo)
• Fix image border in Word2007 Writer for LibreOffice 7 #2021 (kamilmmach)

Miscellaneous

• Corrected namespace for Language class in docs. #2087 (MegaChriz)
• Added support for Garamond font #2078 (artemkolotilkin)
• Add BorderStyle for Cell Style to documentation #2090 (DShkrabak)