Replace boost string algorithms and small improvements

[bernhardmgruber]

• replace the remaining boost string algorithms by the replace_all implementation in the tree mapping. Partially related to Boost #159.
• add a test that VirtualView is constructible using CTAD.
• remove obsolete include directive.
• improve error message on using non-existing tag.
• remove unnecessary size of a VirtualView
• reword View documentation and remove showing direct call of VirtualRecord::operator()