Some cleaning

[fabiencastan]

• change threads
• renaming
• new INSTALL file
• use "with" in browserModel
• use "with" to start/stop workers in ActionManager
• remove singleton
• logging modes

[landscape-bot]

Repository health increased by 0.40% when pulling ffe29e0 on fabiencastan:dev_clean into 87d8c55 on buttleofx:develop.

• 67 new problems were found (including 8 errors and 58 code smells).
• 17 problems were fixed (including 4 errors and 11 code smells).

[landscape-bot]

Repository health decreased by 0.08% when pulling 3d268ce on fabiencastan:dev_clean into 87d8c55 on buttleofx:develop.

• 80 new problems were found (including 14 errors and 65 code smells).
• 23 problems were fixed (including 6 errors and 15 code smells).

[landscape-bot]

Repository health decreased by 0.00% when pulling fd24e30 on fabiencastan:dev_clean into 87d8c55 on buttleofx:develop.

• 79 new problems were found (including 13 errors and 65 code smells).
• 23 problems were fixed (including 6 errors and 15 code smells).

[aoblet]

Included in pull request #174