crash fix for import in BasicHistory

git-svn-id: http://svn.miranda-ng.org/main/trunk@6181 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
code cleaning

git-svn-id: http://svn.miranda-ng.org/main/trunk@6182 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
pre-XP headers cleaned

git-svn-id: http://svn.miranda-ng.org/main/trunk@6183 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
missing file

git-svn-id: http://svn.miranda-ng.org/main/trunk@6184 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
plugins cleanup

git-svn-id: http://svn.miranda-ng.org/main/trunk@6185 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
light speed up for the history erasure

git-svn-id: http://svn.miranda-ng.org/main/trunk@6186 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
minor code cleaning 

git-svn-id: http://svn.miranda-ng.org/main/trunk@6187 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
- unused function removed;
- three wrongly removed lines of code restored

git-svn-id: http://svn.miranda-ng.org/main/trunk@6188 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c