Fix display of variable lines with no variation or with invalid values

See merge request !21

Fix displaying variable values on vertical line

See merge request !20

Re-work the statistic plugin to restore it.

See merge request !19

apply optipng to all png to reduce size

See merge request !18

OTF2: improve support for mpi communicators

See merge request !17

OTF2: implement MPI communicators

See merge request !16

Fix issues reported by SonarQube

See merge request !15

Fix previous commit which broke date parsing & palette creation

Hello,

I fixed the previous commit (a73852cb), which was maybe pushed a little bit too fast ! 😃 

Two things where broken (just by opening a simple trace file):
- date parsing didn't work anymore
- a `delete` lead to a segfault

Philippe.

See merge request !14

Fix issues reported by Sonarqube and warnings reported by the compiler

See merge request !13

Add gitlab analysis

See merge request !11

Resolve "build failure with designated initializers"

Closes #15

See merge request !12

Resolve "Qt4 build failure"

Closes #14

See merge request !10

Resolve "Crashes on extended Event type definition"

Closes #9

See merge request !9